Aim: Early diagnosis and accurate malignant melanoma (MM) staging are significant and decisive in clinical practice. [¹⁸F]DMPY2 is a promising PET tracer in vivo with high affinity and selectivity for melanin. The study aims to investigate the biodistribution and radiation dosimetry in healthy volunteers, and the potential clinical application of [¹⁸F]DMPY2 in MM patients. Materials and Methods: [¹⁸F]DMPY2 was synthesized via a one-pot reaction. The biodistribution, radiation dosimetry, and probe safety were estimated in three healthy volunteers. Thirty-one MM patients underwent [¹⁸F]DMPY2 and/or [¹⁸F]FDG PET/CT scans to explore the clinical use in early detection of melanoma metastasis. Diagnostic performance was assessed in fifty-one LN basins of twenty-seven MM patients after surgery, comparing PET uptake with pathological results. Results: [¹⁸F]DMPY2 was well tolerated by healthy volunteers and MM patients. The calculated effective dose of [¹⁸F]DMPY2 was 0.0122 mSv/MBq. In MM patients, we observed prominent [¹⁸F]DMPY2 tumor uptake and high tumor-to-background ratios in primary tumors. [¹⁸F]DMPY2 showed superior diagnostic performance in lymph node metastases compared to [¹⁸F]FDG, with sensitivity, specificity, accuracy, positive and negative predictive values of 66.7%, 100%, 88.9%, 100% and 85.7%, respectively, versus 50%, 42.9%, 46.7%, 50% and 42.9% for [¹⁸F]FDG. Additionally, [¹⁸F]DMPY2 PET imaging had a unique advantage in distinguishing [¹⁸F]FDG false-positive lesions. Conclusion: [¹⁸F]DMPY2 is a safe and well-tolerated melanin PET tracer and can be a powerful imaging tool for early detection and clinical staging of patients with MM.

Keywords: PET imaging; [18F]DMPY2; early detection; malignant melanoma (MM); melanin.

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目的：早期诊断和准确的黑色素瘤（MM）分期在临床上非常重要。[¹⁸F]DMPY2 是一种有前景的 PET 示踪剂，具有高亲和力和选择性结合黑色素的能力。材料与方法：[¹⁸F]DMPY2 通过一锅法合成。研究估计了该示踪剂在三名健康志愿者中的生物分布、辐射剂量学及探针安全性，并对31 名 MM 患者进行了 [¹⁸F]DMPY2 和/或 [¹⁸F]FDG PET/CT 扫描，以探索其早期检测黑色素瘤转移的临床应用价值。通过比较PET摄取与病理结果，在手术后的27 名 MM 患者的51个淋巴结区域中评估了诊断性能。结果：[¹⁸F]DMPY2 在健康志愿者和MM患者中均耐受良好。计算得出的 [¹⁸F]DMPY2 有效剂量为0.0122 mSv/MBq。在 MM 患者中，我们观察到显着的肿瘤摄取以及原发瘤与背景组织之间的高对比度。^[18F]DMPY2 在诊断淋巴结转移方面优于 ^[18F]FDG，其敏感性、特异性、准确性、阳性预测值和阴性预测值分别为 66.7%、100%、88.9%、100% 和 85.7%，而 ^[18F]FDG 的相应指标为 50%、42.9%、46.7%、50% 和 42.9%。此外，^[18F]DMPY2 PET 成像在区分 ^[18F]FDG 假阳性病灶方面具有独特优势。结论：^[18F]DMPY2 是一种安全且耐受良好的黑色素PET示踪剂，可以成为早期检测和临床分期MM患者的有力成像工具。

关键词：PET 成像；[¹⁸F]DMPY2；早期检测；恶性黑色素瘤（MM）；黑色素。

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